The formulation of cleaning products comprising bleaching agents is a challenging task. Due to their oxidative capacity, bleaching agents are prone to react and destabilize sensitive ingredients such as perfumes, enzymes, etc. As a consequence it is normally necessary to take special measures to ensure the stability of the formulation comprising both the strong oxidants and the bleach sensitive ingredients. Examples of such measures are the segregation of incompatible ingredients in different phases of the formulations (i.e. in different regions of a tablet U.S. Pat. No. 5,133,892), coating one of the ingredients or maintaining it in an isolated state (i.e. by insolubilisation in a liquid matrix) to reduce its interaction with the rest of the formulation.
Problems may not only occur during the storage of the product but also during the cleaning process. When the cleaning product is placed into water and the bleaching agents are released, they can oxidise other ingredients of the cleaning product rather than act on the items to be cleaned, affecting the total efficacy of the product.
Additional problems can appear when the bleaching agent needs to be used in a determined particle size, as in the case of diacyl or tetraacyl peroxide. These kinds of peroxides, which are usually insoluble in water, perform a more efficient bleaching action when the particle size is small. The small particle size also avoids spotting and filming on the cleaned articles. The size limitation can create dusting problems during the manufacturing process, segregation problems in granular detergents and settling problems in liquid detergents.
Due to the above mentioned difficulties an unmet need remains to find a detergent product in which bleaching agent/oxidizing sensitive ingredients interaction is minimized during storage and/or during the cleaning process.